1、Designation:A73990a(Reapproved 2016)Standard Specification forSteel Bars,Alloy,Hot-Wrought,for Elevated Temperature orPressure-Containing Parts,or Both1This standard is issued under the fixed designation A739;the number immediately following the designation indicates the year oforiginal adoption or,
2、in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 Th
3、is specification2covers hot-wrought,ferritic alloysteel bars for elevated temperature or pressure-containing partssuitable for fusion welding or both.1.2 The bars are furnished in the following grades:Grade B 11:1.25%chromium,0.55%molybdenumGrade B 22:2.25%chromium,1.00%molybdenum1.3 The values stat
4、ed in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.2.Referenced Documents2.1 ASTM Standards:3A29/A29M Specification for General Requirements for SteelBars,C
5、arbon and Alloy,Hot-WroughtA370 Test Methods and Definitions for Mechanical Testingof Steel Products3.Ordering Information3.1 Orders for material under this specification shouldinclude the following information:3.1.1 Quantity(weight or number of pieces),3.1.2 Name of material(ferritic alloy steel ba
6、rs),3.1.3 Condition(hot wrought,normalized and tempered,machine straightened and descaled),3.1.4 Dimensions(cross-sectional shape,size,and length),3.1.5 ASTM designation and date of issue,3.1.6 Grade(Table 1),3.1.7 Additions to the specification,and3.1.8 End use.NOTE1A typical description is as foll
7、ows:10 000 lb,Ferritic AlloySteel Bars,Hot Wrought Normalized and Tempered,and Descaled,1.000-in.diameter by 10 ft,ASTM A739 dated_,Grade B11,SpecialStraightened,Special Machined Fittings.4.Materials and Manufacture4.1 Melting PracticeThe steel shall be made by one ormore of the following primary pr
8、ocesses:open-hearth,basic-oxygen,or electric-furnace.The primary melting may incor-porate separate degassing or refining and may be followed bysecondary melting using electroslag remelting or vacuum arcremelting.Where secondary melting is employed,the heatshall be defined as all of the ingots remelt
9、ed from a singleprimary heat.4.2 ConditionUnless otherwise specified,bars shall be hotwrought,heat treated,and descaled.4.3 Heat Treatment:4.3.1 The bars shall be normalized and tempered.4.3.2 Austenitizing temperature shall be within the rangefrom 1700 to 1800F(927 to 982C).4.3.3 Cooling from the a
10、ustenitizing temperature may beaccomplished by cooling in still air or moving air,at theproducers option.When permitted by the purchaser,coolingfrom the austenitizing temperature may be accelerated by sprayor liquid quenching.4.3.4 The minimum tempering temperature shall be 1200F(649C)for Grade B11
11、and 1250F(677C)for Grade B22.5.Chemical Composition5.1 The heat analysis shall conform to the limits for chemi-cal composition specified in Table 1 for the grade ordered.6.Mechanical Properties6.1 Tensile RequirementsThe bars as represented by thetest specimens shall conform to the tensile requireme
12、ntsspecified in Table 2.6.2 SpecimensTension test specimens shall be taken lon-gitudinally and machined from the locations specified in TestMethods and Definitions A370.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct r
13、esponsibility of SubcommitteeA01.15 on Bars.Current edition approved Sept.1,2016.Published September 2016.Originallyapproved in 1976.Last previous edition approved in 2012 as A739 90a(2012).DOI:10.1520/A0739-90AR16.2For ASME Boiler and Pressure Vessel Code applications see related Specifi-cation SA-
14、739 in Section II of that code.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Ba
15、rr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.3 Number of Tests:6.3.1 Two tension tests shall be made to represent bars ofthe same size from each heat in each heat treatment charge.Forcontinuous heat-treated material,not fewer than two tensiontests shall represent a lo
16、t selected on the basis of one tensiontest from each 10 000 lb(4500 kg).6.3.2 When heat treated without interruption in continuousfurnaces,the material in a lot shall be from the same heat,sameprior condition,same size,and subjected to the same heattreatments.6.4 Test MethodsTension tests shall be made in accor-dance with Test Methods and Definitions A370.The yieldstrength shall be determined by the 0.2%offset method.7.Workmanship,Finish,and Appearance7.1 WorkmanshipThe bars shall be free of pip
